Elmer e



E.E.BUTCHER. METHOD OF AND APPARATUS FOR ELIMINATING STATIC EFFECTS.

APPLICATION FILED JULY 20,1915.

1,306,170. I I Ptented June 10, 1919.

nmunn n. nuron in, or INTERLAKEN, NEW mess nssrenon. T0 MARCONI- TELEGRAPH COMPANY or AMERICA, a COBCPORMION or-nnw JERSEY.

' METHOD or am) arrana'rus ron nmmmar ne, sra'ric aoarro.

T 0 all whom it may concern:

Be it known that I, ELMER E. BUTCHER, a citizen of the United States, residing at Interlaken, in the county of Monmouth,

State of New Jersey, have madecertain new 7 and useful Improvements in- Methods of and Apparatus for Eliminating Static Effects in Radio Receiving Apparatus, of which the following is a specification.

This invention relates to a method of and apparatus for eliminating static effects in radio signal receiving apparatus. The object of the invention is to render radio signaling continuously practicable. The in vention comprises the use of an antenna circuit containing adjustable inductance and capacity; two local oscillating circuits each containing adjustable means for causing said circuits to generate or exhibit high frequency oscillations, means for associating said circuits with. athird circuit containing adjustable inductance and capacity; and a receiving device, like a receiving telephone; adjusting or tuning said two local circuits to frequencies above audibility and respectively difierent, and said third circuit to a frequency lower than that characteristic of either the antenna circuit or the two local circuits referred to and within the range of audibility.

.By static it is intended to include an atmospheric disturbance of the electro-equllibrium, such as that due to lightning'discharges, near or remote, or charged particles in the atmosphere which may set up disturbing influences in the receiving apparatus.

There is provided an antenna containing adjustable inductance and capacity and two local oscillating circuits of substantially identical arrangement; each of these circuits contains .an -oscillation generator, like the well-known vacuum valve adjusted to generate high frequency, sustained oscillations, above audibility; these two circuits are so adjusted as to avoid establishing by their characteristic frequency a conjoint note, that is, any note due. to. their coupled cooperation upon a third circuit coupled with said two localcircuits. This third local circuit includes means for tuning and is tuned to a lower frequency than that characteristic of either of said first named local circuits, and preferably to a frequency suitable to the Specification of Letters Patent. Application filed July 20, 1815. Serial No. $0,820.

Errnors.

Patented June in, was.

4. There is a secondary loading coil 10 and variable condenser 11 connected in shunt to inductances 9 and 10. This local circuit also includes thevariabl'econdenser 12, connected Circuit a contains secondary n series with the grid of the vacuum valve 13, one terminal being connected to the high potential terminal of coil 10. Variable condenser 14 is connected in series with inductance coil 15, both being shunted across the high potential, direct current generator ,l6and the primary Winding of the audibility circuit transformer 17. The primary winding 17 is placed in inductive relation to the secondary winding 18. The vacuum valve includes a grid 13, a cold element 19 and a hot element 20; the heating battery and controlling resistance are. shown at 21 and 22, respectively. Coil 15 is placed in coil 10. j

The local oscillatory circuit, 6, contains the variable secondary winding 23; the variable loading coil 24. and the variable condenser 25, connected in shunt to Winding 23 and coil 24. The condenser 26. is connected in series with the grid 27, one terminal of which is connected to the high potential terminal of coil 24. The variable condenser 28 is connected in series with the coil 29, both be and its current varying resistance 35. Cir-- cuits a and b are connected to earth at 36 i h! I u at and 3, as shown. The. prlmary wlnoung of the audlblhty clrcult transformer, 31, is

adjustable inductive relation to v placed in inductive relation to the secondary winding 38. The telephone receiving circuit or audibility circuit, c,contains the windings 18 and 38 and the variable condenser 39, all connected in series. The telephones, 40, are connected in shunt to the variable condenser 39.

The method of operation is as follows: The filament of circuit (1- is brought to a certain degree of incandescence and a certain value of potential selected at thebattery 10, followed by the adjustn'ient of condenser 14 until inductance 15 and condenser 14 have.'fiowing through them, undainped oscillatiim.- The frequency of these oscillations will depend upon the value of capacity selected at the condenser 14. Similar effects are produced by alteration of the value of inductance in use at coil 15. These oscillations are increased 'in amplitude by placing coil 15 in inductive relation to coil 10, followed by a variation of the capacity of condenser 11, or, if desired, by variation of inductance at coils 9 and 10 until the circuit comprising the elements 9, 10 and 11, is in resonance. with the circuit having the elements H and 15. The oscillations flowing in 9, 10 and 11 charge the rid condenser 12 which leaks off to the gri 13, causing corresponding reduction in the current flowing between the hot element 20 and the cold plate 19; both on' account of the trigger action of the valve and the reaction of coil 15 on coil 10 undainped oscillations of increased amplitude are thus maintained in both circuits. The elements 9, 10, 11, 12, 13

and earth connection 36 constitute the grid circuit. The elements 14, 15, 16, 17, 19 and 20 constitute the wing circuit. It is preferred in practice, that the adjustments for frequency in the. grid and wing circuits be made at the condensers 11 and 1-1, condenser 12 generally remalnmg ata fixed small ca- .fre uencydiffering from that of circuit a.

Suc 1 adjustments are made in circuit 6 as to produce beats also above the practical limits of audibility but differing in frequency from those beats in circuit a by a certain. redetermined rate. The'beats produced in both circuits a and b are amplified by the well-known trigger action of the vacuum valve and these beats cause corresponding variation of current through the coils 17 and 31. A change of lines of force takes place in the coils 17 and 31 which cause corresponding alternating current to be set up in the secondary windings 18 and 38, and also the condenser 39. 1f the currents in coils 18 and 38 were identical in frequency and amplitude no sound would be produced in the telephones 40, but if the frequencies in secondary coils 18 and 38 differ by a predetermined amount audible beats suitable to the head telephones 40 will be reduced. The natural frequenc of the telephone circuit may be varied or a tered either by variation of inductance of coils 18 and 38 or by alteration of the capacity or condenser 39.

Since static impulses picked up by the receiving aerial have no distinct time period of vibration, being very highly damped, pure beats are not produced but current pulses of about equal intensity are set up in the primary windings 17 and 31 and by suitable selection of the coupling between coils 17 and 18, also between coils 31 and 38 the resultant currents due to static impulses may be made equal and eppositeand therefore completely neutralize I have discovered that the practical 'range" of audibility for the average magneto receiving telephone is within four or five thousand cycles per second; and in some cases .c less. I have attained good results from tuning the antenna circuit to a frequency of 40,000 cycles; local circuit, a, to 45,000 cycles: local circuit, 1), to 36,000 cycles; the interaction of the 45,000 cycle energy in circuit, (2, upon the 40,000 cycle energy in the antenna circuit will produce in circuit, 0, beats at a rate of 5000 cycles per second which, in turn, will cause 10,000 pulses of current per second in coil 17 of circuit a,- similarly the36,000 cycle energy in circuit, '6, interacting upon'thedlhOOO cycle energy in the antenna circuit will cause a, beat frequency of 4000 cycles per second in circuit, I); this, in turn, will cause 8000 pulses of current r second in primary winding 31 of circuit b. \Ve thus have set up in coll, 18, a fundamental frequency from primary winding, '17, of 5000 cyclesper second and in winding, 38, a fundamental frequency due to winding, 31, of 4000 cycles per second; the interaction of the'frequencies in coils, 38, and, 18, will cause a beat phenomena in circuit, c, of 1000 cycles per second; I am aware that under certain degrees of saturation the coils, 17, and, 31, an alternating current of double frequency .will flow in coils, 18,and, 38, but this will in no wise in:

'terfere with the above-described beat action; it only being then necessary to select a lower order of frequency in coils 17 and 31.

What I claim is: 4 I

1. The method of eliminating static, which consists in subjecting the. received millatuned to a lit) ' ceiving station with cults containing sources of energy, means tionsand the static impulses tothe efiect of the resulting oscillations of the above interentirely elimi-- action in such a manner as to note the resultant oscillations arising from the combination of the static impulses and thelocally generated high frequency oscillations.

2. In a radio signal receiving station, two substantially identical interacting circuits, adapted to generate unlike high frequency oscillations, associated withan antenna circuit, the said generating circuits being inductively coupled to a third circuit comprising a receiving device, said third circuit being tuned to a frequency corresponding to the difi'erence of the frequencies of the tWo interacting circuits.

3. In a radio signal receiving station the combination of an antenna circuit including variable inductance, a local circuit including an oscillation generator of high frequency, a second local circuit including an oscillating generator of high frequency, means for associating both said circuits with the antenna circuit; a third circuit containing tuning devices and a .wave responsive device and means for associating said circuit with said local circuits.

4. In a radlo signal receiving station the combination of an antenna circuit including a variable inductance, cuit including a generator of high frequency oscillations, a second local oscillating circuit including agenerator of high frequency oscillations, means for associatingboth said circuits with the antenna circuit, a third local circuit containing a variable inducta local oscillating cirance and a variable capacity with a receiving telephone and means for associating said circuit with said local circuits.

5. In a radio signal receiving station the combination with the-antenna circuit of two local circuits of substantially identical arrangement containing sources of energy and redetermined frequency and associated with the antenna circuit, a third local circuit tuned to a comparatively low frequency and associated with said local circuits independently of said antenna circuit, a telephone receiver in said third circuit and means for causing the two local circuits and the antenna circuit to react on each other.

6. The combination in a radio signal'reantenna of two local cir-' for causing said local circuits and said antenna to react on each other, a third local circuit, means for associating said third cir-' cuit with both first named local circuits, a receiving device in sald third circuit and 1 means for adjusting said third circuit to a lower frequency than that characteristic of the two local circuits.

' cuit.

' local circuits coupled to said antenna circuit,

the portions of the couplings for said local circuits in said antenna circuit being in series, said local circuits having sources of in dependent electrical impulses therein and being tuned to frequencies one above and one below that of the antenna circuit, and a third local circuit coupled to both the local circuits independently of said antenna cir- 9. The combination in a radio signal re ceiving station of an antenna circuit, two local circuits coupled to said antenna circuit and having sources of independent electrical impulses therein, the portions of the couplings for said secondary circuits in said antenna circuit being in series, and a third local circuit coupled to said other local circuits independently of said antenna circuit, each ofsaid three local circuits containing independent means for varying the natural period thereof.

10. The combination in a radio signal re-' trical impulses, the portions of the couplings A forsaid local circuits in said antenna clrcult being arranged in series, and a third local circuitcoupled to said two first mentioned local circuits independently of said antenna circuit, all three of said local circuits containing means for varying the natural period thereof.

11. In a radio signaling receiving station the combination with an antenna circuit, including inductance and capacity, of two local circuits coupled to said antenna circuit each tuned to a frequency difiering from that of the antenna circuit and differing with respect to each other, a third local circuit separate from said antenna circuit containing variable tuning means and a receiving device, said third local c1rcu1t being tuned to a frequency different from that of either of the two first-named local circuits, and means separate from said antenna circuit for associating said third local circuit with the two first-named local circuits.

' 12. In a radio signaling receiving station the combination with an antenna circuit, including inductance and capacity of two local circuits coupled to said antennacircuit, the portions of the couplings for said local cireach. of said local circuits inclu cuits in said antenna circuit being;1

other, a third local circuit separate from said antenna circuit containing variable tuning mc'ans and a receiving device, and means separate from, said antenna circuit for associating said third local circuit with the two first-named local circuits.

13. In a radio signaling receiving station the combination with an antenna circuit, including inductance and capacity of two local circuits coupled to said antenna circuit, the portions of the couplings for said local circuits in said antenna circuit being in series, each of saidlocal circuits being tuned to a frequency differing from that of the antenna circuit and difi'erm with r spect to each other, a third lo'caf circuit separate from said antenna circuit and containing variable tuning means and a receiving device, and

means separate from said antenna circuit for associating said third local circuit with the two first-named local circuits.

14. In a radio signaling receiving station the combination with an antenna circuit, in-

tuned to a frequency lower than that of the two other lpcal circuits, and means separate from said antenna circuit for -associatingsaid third local circuit with the two firstnamed local circuits.

' ELMER E. BUTCHER. Witnesses:

I. Borromm'r, L. MACCQNNNACH. 

